A novel triangular-shaped plasmonic metal-insulator-metal (MIM) Bragg grating waveguide is introduced, whose band-gap is narrower than that of the conventional step type and wider than that of the sawtoothshaped one. Moreover apodized triangular-shaped MIM Bragg grating structures are proposed in order to reduce the side lobes of the transmission spectrum, because the Bragg reflector with a sawtooth profile has a smoother transmission spectrum than that of a triangular-shaped one. The performance of the proposed structures is simulated by using the finite difference time domain method.

Different configurations of Bragg grating waveguides have been investigated in this paper by the finitedifference time-domain (FDTD) method. By changing the configuration of the gratings, various photonic band-gap widths can be achieved. Moreover the apodized plasmonic metalinsulator-metal (MIM) Bragg grating waveguides whose bandgaps are smoother than the same kind of simple ones are proposed, in order to suppress the side lobs.